The present invention relates to sewage treatment, and especially to on-location, closed circuit treatments in which a sewage-containing liquid is purified and recycled.
While sewage produced in areas served by sewer systems can be treated at a main sewage treatment plant, areas not served by a sewer system commonly employ a septic system wherein raw sewage is delivered to a buried septic tank where the solid matter is broken down by bacteria. Part of the sewage in the tank is discharged into distributing pipes located beneath the ground surface and seeps into the soil where organic matter is further broken down. Besides requiring fresh water to flush toilets, etc., such a system requires land which can percolate sufficiently to drain the water. Thus, areas where percolation is not adequate or where water conservation is demanded are not well suited to conventional septic systems.
There have been heretofore proposed various water purification systems of an on-location type in which sewage is purified and then returned to the toilet(s).
In this regard, it has been proposed to deliver sewage-containing water to a macerator which grinds the solids and discharges same into a treatment chamber where bacterial action decomposes the waste material. Air is circulated within the treatment chamber to promote bacterial decomposition. Treated water is thereafter conducted to a settling chamber where solids settle to the bottom and form a sludge, and the sludge is recycled to the treatment chamber. Water from the settling chamber is conducted through a filter to a holding tank for eventual mixing with waste solids in a toilet.
It has also been proposed to achieve bacterial decomposition of the solids by passing the waste water through a filter upon which the bacterial cultures may breed. The expedient of disinfecting the water with ozone gas has also been proposed.
A problem which is characteristic of many prior art proposals involves the formation of sludge and the need to handle same by removal or recycling. This need adversely affects the convenience and capacity of the system. Also, the requirement of filters can lead to problems if the filters become clogged. Previously suggested on-location systems would have to be quite large and cumbersome, and involve an undesirably long residence time for water being treated, in order to achieve the necessary capacity to service a house or apartment.
It is, therefore, an object of the present invention to provide novel methods and apparatus for purifying sewage-containing liquid.
It is another object of the invention to provide a waste water treatment system which eliminates the formation of sludge.
It is yet another object of the invention to provide a waste water treatment system which effectively and rapidly decomposes waste material.
It is another object of the invention to provide a waste water treatment system which operates relatively rapidly and efficiently so as to be suitable to handle more than one toilet.
It is an additional object of the invention to provide a waste water treatment system which is highly compact and relatively simple in construction and operation.